第一个测试开始后，大约半秒钟后，Xcode会锁定，而不是启动另一个测试。大约30秒后，Xcode崩溃，并且我得到以下崩溃日志（见下文）。
- 我升级到Xcode 11之后才出现这种情况。
- 如果我串行运行单元测试，它就可以正常工作。
- 奇怪的是，似乎只在我的2018年Macbook Pro上发生。在其他Macbooks和Mac Minis上，单元测试能够并行运行而不会崩溃。
- 这只发生在单元测试中。我可以并行运行项目的UI测试。
- 我在同一台机器上有另一个基于框架的项目也遇到了同样的问题。
- 我已经尝试多次删除和重新安装Xcode。
- 编辑：我刚刚尝试擦除Macbook的硬盘并重新安装Mac OS。问题仍然存在。
Process: Xcode [823]
Path: /Applications/Xcode.app/Contents/MacOS/Xcode
Identifier: com.apple.dt.Xcode
Version: 11.0 (14936)
Build Info: IDEFrameworks-14936000000000000~3
App Item ID: 497799835
App External ID: 832762837
Code Type: X86-64 (Native)
Parent Process: ??? [1]
Responsible: Xcode [823]
User ID: 501
Date/Time: 2019-09-23 16:39:38.684 -0700
OS Version: Mac OS X 10.14.6 (18G95)
Report Version: 12
Bridge OS Version: 3.6 (16P6571)
Anonymous UUID: BC74C3A5-0B03-9716-16C5-8C448AD75627
Time Awake Since Boot: 1600 seconds
System Integrity Protection: enabled
Crashed Thread: 27
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFY
Application Specific Information:
ProductBuildVersion: 11A420a
ASSERTION FAILURE in /Library/Caches/com.apple.xbs/Sources/DVTFrameworks/DVTFrameworks-14899/DVTFoundation/Multicore/DVTFuture.mm:376
Details: Attempted to transition to the failed state, but did not provide an error.
<DVTFuture 0x7fc173624f60 Running>
Progress: Initial
Result: (null)
Error: (null)
Started at: 0 -[DVTFuture init] (in DVTFoundation)
1 -[DVTFuture initWithBlock:] (in DVTFoundation)
2 +[DVTFuture futureWithBlock:] (in DVTFoundation)
3 -[DVTiPhoneSimulator launchSimulatedExecutable:launchService:error:] (in IDEiOSSupportCore)
4 __55-[IDELaunchiPhoneSimulatorLauncher performWorkerAction]_block_invoke (in IDEiOSSupportCore)
5 __43-[DVTDispatchLock asyncPerformLockedBlock:]_block_invoke (in DVTFoundation)
6 __DVT_CALLING_CLIENT_BLOCK__ (in DVTFoundation)
7 __DVTDispatchBarrierAsync_block_invoke (in DVTFoundation)
8 _dispatch_call_block_and_release (in libdispatch.dylib)
9 _dispatch_client_callout (in libdispatch.dylib)
10 _dispatch_lane_serial_drain (in libdispatch.dylib)
11 _dispatch_lane_invoke (in libdispatch.dylib)
12 _dispatch_workloop_worker_thread (in libdispatch.dylib)
13 _pthread_wqthread (in libsystem_pthread.dylib)
14 start_wqthread (in libsystem_pthread.dylib)
Finished at: (null)
Object: <DVTFuture: 0x7fc173624f60>
Method: -_internalSetState:result:error:
Thread: <NSThread: 0x7fc17336ae40>{number = 81, name = (null)}
Hints:
Backtrace:
0 -[IDEAssertionHandler handleFailureInMethod:object:fileName:lineNumber:assertionSignature:messageFormat:arguments:] (in IDEKit)
1 _DVTAssertionHandler (in DVTFoundation)
2 _DVTAssertionFailureHandler (in DVTFoundation)
3 -[DVTFuture _internalSetState:result:error:] (in DVTFoundation)
4 __35-[DVTFuture setState:result:error:]_block_invoke (in DVTFoundation)
5 invocation function for block in decltype(fp0()) DVTDispatchLockPerformLockedWriterBlock<void () block_pointer () block_pointer __strong>(DVTDispatchLock*, void () block_pointer () block_pointer __strong) (in DVTFoundation)
6 _dispatch_client_callout (in libdispatch.dylib)
7 _dispatch_lane_barrier_sync_invoke_and_complete (in libdispatch.dylib)
8 DVTDispatchBarrierSync (in DVTFoundation)
9 -[DVTDispatchLock performLockedBlock:] (in DVTFoundation)
10 decltype(fp0()) DVTDispatchLockPerformLockedWriterBlock<void () block_pointer () block_pointer __strong>(DVTDispatchLock*, void () block_pointer () block_pointer __strong) (in DVTFoundation)
11 -[DVTFuture setState:result:error:] (in DVTFoundation)
12 -[DVTFuture failWithError:] (in DVTFoundation)
13 __68-[DVTiPhoneSimulator launchSimulatedExecutable:launchService:error:]_block_invoke (in IDEiOSSupportCore)
14 -[DVTFuture initWithBlock:] (in DVTFoundation)
15 +[DVTFuture futureWithBlock:] (in DVTFoundation)
16 -[DVTiPhoneSimulator launchSimulatedExecutable:launchService:error:] (in IDEiOSSupportCore)
17 __55-[IDELaunchiPhoneSimulatorLauncher performWorkerAction]_block_invoke (in IDEiOSSupportCore)
18 __43-[DVTDispatchLock asyncPerformLockedBlock:]_block_invoke (in DVTFoundation)
19 __DVT_CALLING_CLIENT_BLOCK__ (in DVTFoundation)
20 __DVTDispatchBarrierAsync_block_invoke (in DVTFoundation)
21 _dispatch_call_block_and_release (in libdispatch.dylib)
22 _dispatch_client_callout (in libdispatch.dylib)
23 _dispatch_lane_serial_drain (in libdispatch.dylib)
24 _dispatch_lane_invoke (in libdispatch.dylib)
25 _dispatch_workloop_worker_thread (in libdispatch.dylib)
26 _pthread_wqthread (in libsystem_pthread.dylib)
27 start_wqthread (in libsystem_pthread.dylib)